[PATCH] D27991: Optimize objdump -objc-meta-data

[Dave Lee via Phabricator via llvm-commits]

kastiglione created this revision.
kastiglione added a reviewer: compnerd.
kastiglione added a subscriber: llvm-commits.

Running a Debug build of `objdump -objc-meta-data` with a large Mach-O file is currently unnecessarily slow.

With some local test input, this change reduces the run time from 75-85s down to 15-20s.

The two changes are:

1. Assert on pointer equality not array equality
2. Replace vector<pair<address, symbol>> with DenseMap<address, symbol>


https://reviews.llvm.org/D27991

Files:
  lib/Object/MachOObjectFile.cpp
  tools/llvm-objdump/MachODump.cpp


Index: tools/llvm-objdump/MachODump.cpp
===================================================================
--- tools/llvm-objdump/MachODump.cpp
+++ tools/llvm-objdump/MachODump.cpp
@@ -1780,10 +1780,6 @@
   llvm_unreachable("Input object can't be invalid at this point");
 }
 
-typedef std::pair<uint64_t, const char *> BindInfoEntry;
-typedef std::vector<BindInfoEntry> BindTable;
-typedef BindTable::iterator bind_table_iterator;
-
 // The block of info used by the Symbolizer call backs.
 struct DisassembleInfo {
   bool verbose;
@@ -1797,7 +1793,7 @@
   char *demangled_name;
   uint64_t adrp_addr;
   uint32_t adrp_inst;
-  BindTable *bindtable;
+  SymbolAddressMap *bindtable;
   uint32_t depth;
 };
 
@@ -9427,29 +9423,19 @@
 static const char *get_dyld_bind_info_symbolname(uint64_t ReferenceValue,
                                                  struct DisassembleInfo *info) {
   if (info->bindtable == nullptr) {
-    info->bindtable = new (BindTable);
+    info->bindtable = new (SymbolAddressMap);
     SegInfo sectionTable(info->O);
     for (const llvm::object::MachOBindEntry &Entry : info->O->bindTable()) {
       uint32_t SegIndex = Entry.segmentIndex();
       uint64_t OffsetInSeg = Entry.segmentOffset();
       if (!sectionTable.isValidSegIndexAndOffset(SegIndex, OffsetInSeg))
         continue;
       uint64_t Address = sectionTable.address(SegIndex, OffsetInSeg);
-      const char *SymbolName = nullptr;
       StringRef name = Entry.symbolName();
       if (!name.empty())
-        SymbolName = name.data();
-      info->bindtable->push_back(std::make_pair(Address, SymbolName));
+        (*info->bindtable)[Address] = name;
     }
   }
-  for (bind_table_iterator BI = info->bindtable->begin(),
-                           BE = info->bindtable->end();
-       BI != BE; ++BI) {
-    uint64_t Address = BI->first;
-    if (ReferenceValue == Address) {
-      const char *SymbolName = BI->second;
-      return SymbolName;
-    }
-  }
-  return nullptr;
+  auto name = info->bindtable->lookup(ReferenceValue);
+  return !name.empty() ? name.data() : nullptr;
 }
Index: lib/Object/MachOObjectFile.cpp
===================================================================
--- lib/Object/MachOObjectFile.cpp
+++ lib/Object/MachOObjectFile.cpp
@@ -2823,7 +2823,9 @@
 }
 
 bool MachORebaseEntry::operator==(const MachORebaseEntry &Other) const {
-  assert(Opcodes == Other.Opcodes && "compare iterators of different files");
+  assert(
+      (Opcodes.begin() == Other.Opcodes.begin() || Opcodes == Other.Opcodes) &&
+      "compare iterators of different files");
   return (Ptr == Other.Ptr) &&
          (RemainingLoopCount == Other.RemainingLoopCount) &&
          (Done == Other.Done);
@@ -3073,7 +3075,9 @@
 int MachOBindEntry::ordinal() const { return Ordinal; }
 
 bool MachOBindEntry::operator==(const MachOBindEntry &Other) const {
-  assert(Opcodes == Other.Opcodes && "compare iterators of different files");
+  assert(
+      (Opcodes.begin() == Other.Opcodes.begin() || Opcodes == Other.Opcodes) &&
+      "compare iterators of different files");
   return (Ptr == Other.Ptr) &&
          (RemainingLoopCount == Other.RemainingLoopCount) &&
          (Done == Other.Done);


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